US-12616719-B2 - Dispersion solution of complex of cerium oxide nanoparticle with protein, method of scavenging reactive species, and method of producing dispersion solution of complex of cerium oxide nanoparticle with protein

US12616719B2US 12616719 B2US12616719 B2US 12616719B2US-12616719-B2

Abstract

A dispersion solution contains a complex of cerium oxide nanoparticle with protein in which a hydrodynamic diameter and zeta potential of the protein are maintained. The dispersion solution is produced by mixing a solution containing the protein with a solution containing a cerium (III) ion or with a cerium (III) salt followed by adding an oxidizing agent thereto.

Inventors

Shota Sekiguchi
Takahiro Motoshiromizu
Masateru Ito

Assignees

TORAY INDUSTRIES, INC.

Dates

Publication Date: 20260505
Application Date: 20201225
Priority Date: 20191226

Claims (5)

1 . A method of producing a dispersion solution of a complex of cerium oxide nanoparticle with protein, the method comprising: mixing a solution containing the protein with a solution containing a cerium (III) ion or with a cerium (III) salt; and adding an oxidizing agent thereto to produce a dispersion solution of a complex of cerium oxide nanoparticles with protein, the oxidizing agent oxidizing a cerium (III) ion to cerium (IV), and the cerium oxide nanoparticles consisting of a mixture of Ce 2 O 3 and CeO 2 , wherein the oxidizing agent is selected from the group consisting of nitric acid, potassium nitrate, hypochlorous acid, chlorous acid, chloric acid, perchloric acid, halogens, permanganate salts, chromic acid, dichromic acid, sulfuric acid, or hydrogen peroxide.
2 . The method according to claim 1 , wherein a molecular weight of the protein is 5 kD to 200 kD.
3 . The method according to claim 1 , wherein the protein is a protein present in blood.
4 . The method according to claim 1 , wherein the protein is albumin or globulin.
5 . The method according to claim 1 , wherein an addition amount of the oxidizing agent relative to the cerium (III) ion as a molar equivalent is 0.1 to 10.

Description

TECHNICAL FIELD This disclosure relates to a dispersion solution of a complex of cerium oxide nanoparticle with protein, a method of producing the said dispersion solution, and a method of scavenging reactive species using the dispersion solution. BACKGROUND Oxidative stress damages cells in the living body, and it is said that this is related to cardiovascular diseases such as myocardial infarction and cerebral infarction, neurological diseases such as ALS and Parkinson's disease, cancer, inflammation, and aging. Because the causative substances of the oxidative stress are reactive species (reactive oxygen species (ROS) and reactive nitrogen species (RNS)) generated in the living body, an anti-oxidative technology to scavenge these reactive species is considered important in health management and disease prevention. For example, the anti-oxidative technology is used in various ways in our daily lives such as taking vitamin C from foods or applying astaxanthin to skin to protect the skin and cells. Such anti-oxidative technologies are also expected to be used in medical situations such as applying an antioxidant to a catheter to suppress inflammation or delivering an antioxidant to a site of disease through a blood vessel. Therefore, it is necessary to improve the biocompatibility and retentivity in blood. If the protein, which is abundant in the body, can be provided with an anti-oxidative property, it is expected that this can be used as an antioxidant having high biocompatibility and retentivity in blood. One possible way to provide a protein with an anti-oxidative property is to complex it with an antioxidant such as a vitamin, but such an antioxidant is generally active in a consumable form, so this does not have a durable effect. Therefore, it is desirable to complex it with a material having a durable anti-oxidative property. On the other hand, a cerium oxide nanoparticle (nanoceria) has an anti-oxidative property. It is known that this has a catalytic activity similar to such enzymes as a catalase and a superoxide dismutase. It is also reported that this, due to the antioxidative property thereof, is related to the therapeutic effect against Parkinson's disease, to reduction in the damage from an ischemic disease that occurs during cerebral infarction, and to improvement in the sperm motility. Because cerium oxide is a ceramic, it is chemically stable and has a durable anti-oxidative property. Therefore, if a protein can be complexed with a cerium oxide nanoparticle, it is expected that the protein can be provided with a durable anti-oxidative property. In this context, Swanand Patil, et al., “Protein Adsorption and Cellular Uptake of Cerium Oxide Nanoparticles as a Function of Zeta Potential,” Biomaterials 2007, 28, 4600-4607 and Roman Marsalek, “Adsorption of Bovine Serum Albumin on CeO2” Int. J. Bioeng. and Life Sci. 2014, 8, 1346-1349 disclose that when the nanoceria is mixed with BSA, which is a protein, the BSA is adsorbed onto the surface of nanoceria, and the adsorption amount thereof varies depending on the pH of the solution or on the electric potential of the nanoceria. Also, FIG. 4C of Biwu Liu, et al., “Boosting the Oxidase Mimicking Activity of Nanoceria by Fluoride Capping: Rivaling Protein Enzymes and Ultrasensitive F− Detection,” Nanoscale 2016, 8, 13562-13567 discloses that the enzymatic activity of the nanoceria is decreased when the nanoceria is mixed with BSA. With the aim to obtain an antioxidant having high biocompatibility and retentivity in the blood, we studied obtaining a dispersion solution having a cerium oxide nanoparticle complexed with protein, wherein the solution has an anti-oxidative property. However, as described in Comparative Examples later, when the methods described in Patil, et al. and Marsalek were applied, aggregation of the complex occurred, thereby leading to a significant increase in the hydrodynamic diameter thereof. Under other conditions, aggregation could be suppressed, but the electrostatic properties of the complex as indicated by the zeta potential deviated significantly from those of the protein. As a result, in the complexes obtained by the methods described in Patil, et al. and Marsalek, there occurred the problems of the loss of the biocompatibility and the retentivity in the blood, which are the properties characteristic of the protein. It therefore became apparent that it could be helpful to provide a dispersion solution of a complex of cerium oxide nanoparticle with protein while the hydrodynamic diameter and zeta potential of the protein are maintained. SUMMARY We studied ways to complex the cerium oxide nanoparticle with the protein. As a result, we found that by mixing a solution containing a protein with a solution containing a cerium (III) ion or with a cerium (III) salt followed by adding an oxidizing agent, thereby producing a complex, the cerium oxide nanoparticle and the protein can be complexed while the hydrodynamic diameter and